How to restart/delete an instance of mongod? - mongodb

Question

This has been covered in other SO posts, but unfortunately those solutions are not working.
How does one restart/delete a mongod instance?
Entering
$ mongod
I get the following error:
2016-01-24T09:49:19.557-0500 I CONTROL [initandlisten] MongoDB starting : pid=43675 port=27017 dbpath=/data/db 64-bit host=NAME-MacBook-Pro.local
2016-01-24T09:49:19.558-0500 I CONTROL [initandlisten] db version v3.0.8
2016-01-24T09:49:19.558-0500 I CONTROL [initandlisten] git version: 83d8cc25e00e42856924d84e220fbe4a839e605d
2016-01-24T09:49:19.558-0500 I CONTROL [initandlisten] build info: Darwin NAME-MacBook-Pro.local 15.2.0 Darwin Kernel Version 15.2.0: Fri Nov 13 19:56:56 PST 2015; root:xnu-3248.20.55~2/RELEASE_X86_64 x86_64 BOOST_LIB_VERSION=1_49
2016-01-24T09:49:19.558-0500 I CONTROL [initandlisten] allocator: system
2016-01-24T09:49:19.558-0500 I CONTROL [initandlisten] options: {}
2016-01-24T09:49:19.558-0500 E NETWORK [initandlisten] listen(): bind() failed errno:48 Address already in use for socket: 0.0.0.0:27017
2016-01-24T09:49:19.558-0500 E NETWORK [initandlisten] addr already in use
2016-01-24T09:49:19.558-0500 I STORAGE [initandlisten] exception in initAndListen: 98 Unable to create/open lock file: /data/db/mongod.lock errno:13 Permission denied Is a mongod instance already running?, terminating
2016-01-24T09:49:19.558-0500 I CONTROL [initandlisten] dbexit: rc: 100
I explicitly gave myself permissions with
sudo chown -R <USERNAME> /data/db
This didn't work.
I tried to remove the directory entirely
sudo rm -rf /data/db
and recreate it
mkdir -p /data/db
but unfortunately this doesn't work.
I thought the solution would be to remove the file /data/db/mongod.lock but it doesn't exist:
rm /data/db/mongod.lock
Anything else I should try?
EDIT: After running with the different port using mongod --port 12345, when I use use admin and then db.shutdownServer(), I get the following error:
2016-01-24T10:32:25.039-0500 I NETWORK trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2016-01-24T10:32:25.039-0500 I NETWORK reconnect 127.0.0.1:27017 (127.0.0.1) ok
2016-01-24T10:32:25.040-0500 I NETWORK DBClientCursor::init call() failed
server should be down...
EDIT 2:
Restarting the machine does nothing. I've tried to access the default port with mongod --port 27017, and then
> use admin
> db.shutdownServer()
I get the output:
2016-01-25T12:05:32.163-0500 I NETWORK DBClientCursor::init call() failed
server should be down...
2016-01-25T12:05:32.166-0500 I NETWORK trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2016-01-25T12:05:32.166-0500 W NETWORK Failed to connect to 127.0.0.1:27017, reason: errno:61 Connection refused
2016-01-25T12:05:32.166-0500 I NETWORK reconnect 127.0.0.1:27017 (127.0.0.1) failed failed couldn't connect to server 127.0.0.1:27017 (127.0.0.1), connection attempt failed

Answer 1

In the log it say:
2016-01-24T09:49:19.558-0500 E NETWORK [initandlisten] listen(): bind() failed errno:48 Address already in use for socket: 0.0.0.0:27017
2016-01-24T09:49:19.558-0500 E NETWORK [initandlisten] addr already in use
It means that the port is already in use either by another process or another mongo instance.
You should use another port for this instance.
Refer to this link